This invention relates to curable compositions for drugs having sustained release property, and more particularly to curable compositions for dental drugs having sustained release property, cured polymerizates thereof and methods for preventing dental diseases wherein active ingredients of said drugs are gradually released in the mouth over a long period of time, thereby preventing dental diseases such as carious tooth, pyorrhea alveolaris, etc.
Carious tooth which is most frequently observed in dental diseases is caused by various oral microorganisms (Streptococcus mutans is well known out of these microorganisms) present in the mouth. On one hand, such dental diseases as pyorrhea alveolaris and others are induced by the bacteria contained in dental plaque. Accordingly, an effective means to prevent such dental diseases as carious tooth, pyorrhea alveolaris, etc. is to inhibit propagation of bacteria in the mouth as well as formation of dental plaque.
Under the circumstances, we have studied various drugs from the standpoint of preventive dentistry, and eventually have come to the conclusion that in order to inhibit the propagation of bacteria in the mouth as well as the formation of dental plaque, the use of crude drug ingredients having bactericidal activities is effective for the purpose intended since they bring about less side-effects even when administered for an extended period of time, assuring safety in application and mild activities. However, a mere application of such crude drug ingredients directly to intra-oral sites results in unsustained pharmacological effect of said crude drug ingredients, and thus no desired effect can be achieved.
Now, we have made further study in view of the above, and found that if crude drug ingredients having bactericidal activities are applied to intra-oral sites in the sustained release form, the bactericidal ingredients are gradually released to effectively inhibit the formation of dental plaque and the propagation of bacteria in the mouth over a long period of time, and hence it is advantageous to formulate the crude drug ingredients into the preparations having sustained release property wherein said ingredients are incorporated in a suitable matrix.
Preparation of drugs having sustained release property by including active ingredients of the drugs in a polymer matrix is disclosed in Japanese Patent Laid-Open-to-Public No. 62012/1980 and Japanese Patent Publn. No. 17001/1982. The drugs disclosed in these publications, however, are all directed to the treatment of internal diseases occurring in digestive canals, systems of circulation, etc. and are applied to in oral dosage forms or applied to mucous membrane in the mouth and are not intended to the prevention of dental diseases such as carious tooth, pyorrhea alveolaris, etc. So far as we are aware of, it is not known that crude drug ingredients are formulated into drugs having sustained release property for the purpose of preventing dental disease.
An object of the invention is to provide curable compositions for preparing drugs having sustained release property which are highly effective in preventing such dental diseases as carious tooth, pyorrhea alveolaris, etc. in a simple and practicaly easy manner.
These and other objects of the invention will be apparent from the following detailed description thereof.